Keyboard Test
Press your keys one at a time. It shows keys that don't register, chatter (the same key again within 100ms) and how many keys register at once (rollover).
On-screen keyboard
- Keys checked
- 0 / 104
- Held now
- 0
- Most at once
- 0
- Possible chatter
- 0
Press any key to start. No need to click anything, just type on this page.
Last key - since the previous press of this key: - ms
The window lost focus, so every held key was released on screen. Press keys again to continue.
A phone or tablet's on-screen keyboard cannot be tested here. Connect a physical keyboard and it works the same way.
Tab and Enter are tested like other keys. Press Esc to pause and move around with Tab.
Test paused. Key presses are no longer recorded and Tab moves around the page.
- Pressed at least once
- Held right now
- Possible chatter (repeated within 100ms)
Keys outside the layout
Some keys may be chattering
These keys came in again within 100ms. If they're still flagged when pressed slowly, one at a time, chatter is likely.
Mouse Test Mouse Polling Rate Test Reaction Time Test Monitor Refresh Rate Test FPS Drop and Stutter Cause Checker
How to test your keyboard
- Press every key onceA key that never lights up didn't reach your PC. Keys your keyboard doesn't have (like a tenkeyless number pad) stay dark, which is normal.
- Re-press suspect keys slowlyPress flagged keys slowly, one at a time. If still flagged, the switch is the likely cause.
- Hold the keys you play withHold your usual game keys together, add one more at a time and watch how high "Most at once" goes.
What to check when a key does not register
- If it stays dark on another USB port and another PC, the keyboard is the cause.
- With Windows Filter Keys on, brief or repeated keystrokes can be ignored. Check Settings > Accessibility > Keyboard.
- Some keys are blocked by the keyboard itself, such as a gaming mode or a Windows key lock. Check the maker's manual.
Keyboard chatter: what to check, in order
Chatter is a keyboard fault caused by a worn or dirty switch. Windows Bounce Keys or a chatter blocker only hide the symptom; they don't repair the switch.
- Try another USB port and another PCIf it repeats on another port and another PC, the keyboard is the cause. For wireless, also try it wired.
- Pull the keycap and clean itRemove the keycap with a keycap puller and blow out the dust. If anything was spilled on the keyboard, the contacts may be contaminated.
- Check the debounce settingIf the maker's software or firmware has a debounce setting, raise it a little. Too high and fast taps can be dropped.
- Replace the switch or get it repairedOn a hot-swap keyboard, replace just that switch. Otherwise, use the maker's warranty repair.
Rollover (NKRO) and ghosting test
Hold your game keys (for example W, A, Shift and Space) and add more one at a time. If "Held now" stops rising or a key doesn't light up, that combination isn't registered at once.
If a key you did not press lights up while you hold several keys, that is ghosting. Repeat the same combination a few times and see whether the same key lights up.
That pop-up after five Shift presses isn't a fault
It's the Windows Sticky Keys shortcut. Lutimize (our app) turns it off and sets the key repeat delay to the shortest. Lutimize doesn't repair faulty keys.
How it works and its limits
Keys light up by physical position (code), so the same key lights the same spot whatever your language or layout. A press of the same key within 100ms counts as possible chatter; auto-repeat while holding does not.
- The Fn key is usually handled inside the keyboard and never reaches the PC, so it doesn't show.
- Keys the browser or Windows handle first, such as Ctrl+W, Alt+Tab, Ctrl+Alt+Delete and Win shortcuts, can't be blocked here.
- In some browsers the Print Screen key only reports its release, so it may never show as held.
- The on-screen keyboard is a 104-key full-size layout. Keys not on it (such as the Japanese Henkan and Muhenkan keys) show by name under "Keys outside the layout".
- Keyboard input latency can't be measured: the browser only knows when the PC received the input. The ms shown is the gap between presses of the same key.
- The keys you press (names, counts, gaps) are never sent to our server or analytics. This tool logs just two events, that it was used and whether chatter was flagged; the site's usual visit statistics are recorded as on any page.
Common questions
How do I check if my keyboard is broken?
Press every key once and look for keys that don't light up. If one stays dark on another USB port and another PC, the keyboard is at fault (some keys, like Fn, never send a signal).
What is keyboard chatter?
It's when one press types a key two or more times. It happens when a worn or dirty switch makes the signal bounce longer than usual.
Why is the chatter threshold 100ms?
A key that comes in again within 100ms is flagged; that's the default of an open-source chatter blocker. Fast tapping can land inside it too, so press flagged keys slowly to confirm.
Can this measure keyboard input lag?
No. The browser only knows when the PC got the input, so keyboard delay can't be measured; for how often a mouse reports, try the mouse polling rate test.
How many keys at once is normal?
There's no fixed normal; it varies by keyboard. The basic USB report holds up to six regular keys besides modifiers like Shift and Ctrl, so stopping at six may mean your keyboard uses that format.
Does it work with JIS or ISO layout keyboards?
Yes. The on-screen keyboard uses the 104-key US layout, and keys outside it (such as the Japanese Henkan and Muhenkan keys) appear by name under "Keys outside the layout".
Can I measure my keyboard's polling rate?
Not here: a keyboard only sends input when a key is pressed or released. You can measure a mouse with the mouse polling rate test.
Do I need to install anything?
No. Just press keys in the browser where this page is open. It is free and needs no account.
Are my key presses saved or sent anywhere?
No. Key presses are never sent to our server or added to the page address.
Last reviewed 2026-11-08